Expose native storage retention for VM and CT backups

tests/test_backup_storage_retention.cjs

@@ -0,0 +1,27 @@
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const vm = require('node:vm');
+const ts = require('typescript');
+const source = fs.readFileSync('AppImage/lib/backup-retention.ts', 'utf8');
+const context = { exports: {} };
+vm.runInNewContext(ts.transpileModule(source, { compilerOptions: { module: ts.ModuleKind.CommonJS } }).outputText, context);
+const { parseRetention, buildRetention } = context.exports;
+for (const policy of ['keep-all=1', 'keep-last=3', 'keep-last=3,keep-weekly=2', 'keep-hourly=24,keep-daily=7,keep-monthly=12,keep-yearly=2']) {
+  const { fields, keepAll } = parseRetention(policy);
+  assert.equal(buildRetention(fields, keepAll), policy);
+}
+assert.equal(buildRetention({}, false), '', 'empty policy remains explicit');
+assert.equal(buildRetention({}, true), 'keep-all=1');
+assert.equal(buildRetention({ daily: '3', hourly: '0', last: '' }, false), 'keep-daily=3');
+assert.equal(buildRetention({ last: '3' }, true), 'keep-last=3', 'existing job editor precedence preserved');
+const component = fs.readFileSync('AppImage/components/backup-storage-retention.tsx', 'utf8');
+const english = JSON.parse(fs.readFileSync('AppImage/messages/en/common.json')).backup.storageRetention;
+for (const [, key] of component.matchAll(/t\("backup\.storageRetention\.([A-Za-z]+)"/g)) {
+  assert.ok(typeof english[key] === 'string' && english[key], `translation: ${key}`);
+}
+assert.ok(component.includes('digest: editing.digest'));
+assert.ok(component.includes('method: "PUT"'));
+assert.ok(!component.includes('/prune'));
+assert.ok(fs.readFileSync('AppImage/components/vm-backup-jobs.tsx', 'utf8').includes('from "../lib/backup-retention"'));
+assert.ok(fs.readFileSync('AppImage/components/backup-tab.tsx', 'utf8').includes('<BackupStorageRetention />'));
+console.log('PASS: shared native retention properties, keep-all/count round trips, explicit empty policy, translations and digest wiring');